I watched this movie for the first time last night. I didn't like it as much as "Back to Bataan" or "Sands of Iwo Jima", but it was really good.
It was very obviously a John Ford film, though, and I think that's what made me really like it. His masterful use of snatches of old songs at the right moments is frequently very moving. I noticed that at least twice he included the "Battle Cry of Freedom" moving into the "Battle Hymn of the Republic" (which appeared again as the closing song. Epic!!) But especially poignant was the use of "Red River Valley" when the old mechanic stayed behind.
The other thing about John Ford is that he has such a talented way of subtly bringing out character's emotions (without over-dramatization) and making a film more human. I especially liked the way he showed the women's struggle to remain feminine while having to be tough, as they endured the horrors of war.
Of course, this was also an excellent acting performance by the Duke, ably seconded by Robert Montgomery. You can still see Duke growing in acting prowess, but his classic persona is already there.
Overall, I really liked "They Were Expendable" and will be adding it to my film collection. Another score for the Duke and John Ford!
I've always liked that one song they played every time Wayne and Donna Reed were together. Nice romantic touch. Plus, I recently bought a Blu-ray copy of this and it looks great. PQ looks sharp and clear.